1. Technical Field
The present invention generally relates to computer systems, and more particularly to a method of dynamically adjusting an audio subsystem of a computer system to support different types of audio output devices, e.g., speakers or headphones.
2. Description of Related Art
A typical structure for a conventional computer system includes one or more processing units connected to a system memory device (random access memory or RAM) and to various peripheral, or input/output (I/O), devices such as a display monitor, a keyboard, a graphical pointer (mouse), and a permanent storage device (hard disk). The system memory device is used by a processing unit in carrying out program instructions, and stores those instructions as well as data values that are fed to or generated by the programs. A processing unit communicates with the other components by various means, including one or more interconnects (buses), or direct access channels. A computer system may have many additional components, such as serial, parallel, and universal serial bus (USB) ports for connection to, e.g., printers, and network adapters. Other components might further be used in conjunction with the foregoing; for example, a display adapter might be used to control a video display monitor, a memory controller can be used to access the system memory, etc.
One other common feature of modem computers is audio capability. Many computers have built-in speakers, some offering quality stereo listening, not only in desktop computers, but in portable (laptop or notebook) computers as well. Desktop and portable computers also commonly provide an audio subsystem I/O device on the main circuit board (“motherboard”), having one or more jacks for connecting to various audio devices, such as speakers, headphones, microphones, MIDI music sources, etc. The ports for a typical audio subsystem are illustrated in FIG. 1. The ports are mounted on the motherboard 1 and include a line in jack 2, a line out jack 3, and a mic in jack 4. Line in jack 2 receives a plug from an audio source (i.e. cassette deck) 5, line out jack 3 receives a plug from a speaker pair 6, and mic in jack 4 receives a plug from a microphone 7. This configuration is typical of various computer types, particularly those computers referred to as IBM-compatible, or personal computers (PCs).
Many computer vendors are driving the strategic direction of the consumer brand of PCs towards the direct model. This model is based on the idea of building a PC towards a customer's unique requirements or specifications. One area of concern in this regard has been the audio subsystem. The computer manufacturer cannot know at the factory what kind of audio devices may ultimately be installed on a unit; for example, a model may be shipped with “passive” speakers, or “active” speakers. Passive speakers are those having minimal integrated electronics and no power supply (typically small speakers). Active speakers are powered by a separate power source. To achieve the lowest possible cost for a consumer model, an audio amplifier can be mounted on the motherboard to provide adequate power for passive audio speakers. Such a setup requires the passive speakers to be powered from a separate jack with, e.g., three watts per channel. If one wishes to upgrade to a set of external active speakers (requiring a power AD/DC power adapter), they must be powered from another jack (line out jack 3), which is typically powered with one-quarter watt per channel.
In the foregoing design, the planar (motherboard) provides both a line-out jack and a speaker out jack, but it is extremely rare that both of these ports would be in use. There is accordingly a cost increase of the planar due to the additional connectors and circuitry, and the size (area) of the planar is further negatively impacted. As the area of planars continues to decrease, there is less board edge to place these additional connectors. Another problem with providing two audio output jacks is the resulting customer confusion as to which jack is to be used. This confusion not only leads to excessive support calls which cost the manufacturer, but can further damage the audio subsystem (from overdriving active speakers).
One solution to the foregoing problem is to simply provide only one audio output jack, and allow the customer to make appropriate hardware or software adjustments depending upon the intended audio output device. For example, a physical switch (jumpers) may be provided on the planar board, and the customer must open up the cover, go inside the PC and set the jumpers depending upon whether they wish to use passive or active speakers. If the customer orders a model (which is shipped preset for passive speakers) and they also order an upgraded pair of active speakers, the customer will have to open up the cover and change jumper settings to set the PC for active speakers. The primary problem with this approach is that, if the customer opens up the box and accidently manipulates the wrong set of jumpers (or otherwise damages any internal components), then the warranty for the PC becomes invalid. Also, if the customer sets these particular jumpers incorrectly, it can damage (overdrive) their active speakers, or they will not hear anything from their passive speakers. Either result again leads to increased costs on the manufacturer's part for support calls, as well as shipping new parts to replace damaged goods.
Alternatively, the customer can make software adjustments, e.g., in the computers' basic input/output system (BIOS) to select either passive or active speakers. This approach requires the customer to enter the BIOS setup screen and modify the BIOS settings, but most consumers are unfamiliar with this process. This solution assumes the customer reads the relevant documentation first, but this is rarely the case. Most manufacturer's dislike customers adjusting BIOS settings unless it is critically necessary. If a customer accidentally makes an incorrect change to the BIOS settings, it may lead to severe trouble. There is generally no reason to take such risks just to support a speaker, and incorrect changes can again result in support calls, delivering new parts, and quality perception. It is also possible that incorrect settings may damage active speakers.
In light of the foregoing it would be desirable to provide an improved method of determining which type of speaker is connected to the audio subsystem, and to power it appropriately. It would be further advantageous if the method did not require user intervention so as to avoid problems associated with incorrect user adjustments.